This relates generally to imaging systems, and more particularly, to multi-channel imaging systems in which multiple image streams from the same pixel array share a common interface transport.
Modern electronic devices such as cellular telephones, cameras, video cameras and computers often use digital image sensors. Imagers (i.e., image sensors) may include a two-dimensional array of image sensing pixels. Each pixel receives incident photons (light) and converts the photons into electrical signals. High-speed complementary metal-oxide-semiconductor (CMOS) image pixel arrays enable high-resolution image frames to be read out at high frame rates resulting in, for example, 16 Megapixel images delivered to an image signal processor at 60 frames per second (i,e., 16 Mp60). Many image signal processors cannot process this much data in a streaming mode (e.g., video mode). This creates the need for additional image buffers that buffer an image frame before processing and may require excess amounts of power consumption by the image signal processor. Conventional image sensors may include a resizer circuit to deliver reduced resolution HD video to an image signal processor resulting in smaller amounts of data delivered to an image signal processor and lower power consumption than delivering full resolution streaming data.
Some conventional image sensors include a JPEG compressor for creating JPEG compressed snapshot images which are then combined (e.g., using a multiplexer) with the video stream on a single output channel. JPEG compression of snapshot images reduces the data rate on the output channel, however, valuable image data is lost in both a video resizing and a JPEG compressing operation.
It would therefore be desirable to provide electronic devices with improved image sensors that provide both high-resolution snapshot and resized video image data to an image signal processor.